nano: update to 4.1

nano: update to 4.1

* update nano to 4.1
* implement Makefile style changes proposed in #8483

Release notes at https://nano-editor.org/news.php

2019.04.15 - GNU nano 4.1
* By default, a newline character is again automatically added at the
  end of a buffer, to produce valid POSIX text files by default, but
  also to get back the easy adding of text at the bottom.
* The now unneeded option --finalnewline (-f) has been removed.
* Syntax files are read in alphabetical order when globbing, so that
  the precedence of syntaxes becomes predictable.
* In the C syntax, preprocessor directives are highlighted differently.
* M-S now toggles soft wrapping, and M-N toggles line numbers.
* The jumpy-scrolling toggle has been removed.
* The legacy keystrokes ^W^Y and ^W^V are recognized again.
* Executing an external command is disallowed when in view mode.
* Problems with resizing during external or speller commands were fixed.

Tested with ipq806x R7800

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>